Merge pull request #16505 from sgrif/sg-attribute-internals

Use the method for determining attribute methods rather than duplicating
prefer `has_attribute?` over `attributes.key?`.

Follow up to the discussion on #16505.
fix typo in method name (broken build :sweat:)
Fixed link for in_place_editor [ci skip]

closes #16512
Point to rubygems instead of Rails GitHub. [ci skip]

The rails repository is not the official plugin anymore
Implement `==` on `Type::Value` and `Attribute`

This was a small self contained piece of the refactoring that I am
working on, which required these objects to be comparable.
Use *_transaction methods in TransactionManager

Use `commit_transaction`/`rollback_transaction` on
`within_new_transaction` method, so they make sure they `pop` the
transaction from the stack before calling the methods `commit`/`rollback`.
Fix regression on after_commit in nested transactions.

after_commit should not run in nested transactions, however they should
run once the outermost transaction gets committed. This patch fixes the
problem copying the records from the Savepoint to its parent. So the
RealTransaction will have all records that needs to run callbacks on it.

[fixes #16425]
Removed method missing from ActionMailer::MessageDelivery
Merge pull request #16435 from arthurnn/after_commit_run_on_top_level_trans_master

Fix regression on after_commit in nested transactions. (master)
ActiveJob: Reworked queue_base_name as default_queue_name + Allow configure ActiveJob from app.config.active_job
Suggest the perform method can take arguments when generating an ActiveJob job
Moved AR testing from using global variable to thread variable
Fixed indentation
Added docs for AJ::Callbacks; Added AJ to docs build map
Unused ivar in a test suite
Avoid polluting String class globally in a test case
Avoid mutating the constants in a test case
[ci skip] Update links in getting_started guide.
ActiveJob guides improvements [ci skip]